CoMoS catalyst preparation method using a triblock copolymer

ABSTRACT

A method of preparing hydrodesulfurization catalysts having cobalt and molybdenum sulfide deposited on a support material containing mesoporous silica. The method utilizes a sulfur-containing silane that dually functions as a silica source and a sulfur precursor. The method involves an one-pot strategy for hydrothermal treatment and a single-step calcination and sulfidation procedure. The application of the hydrodesulfurization catalysts in treating a hydrocarbon feedstock containing sulfur compounds to produce a desulfurized hydrocarbon stream is also specified.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. Application No.16/519,300, pending, having a filing date of July 23, 2019.

BACKGROUND OF THE INVENTION Technical Field

The present disclosure relates to a method of making catalystscontaining cobalt, molybdenum and sulfur supported by mesoporous silicavia a single-step calcination and sulfidation strategy, catalysts madeby the process, and a process of hydrodesulfurization using thecatalysts.

Description of the Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

To meet environmental regulations that limit sulfur content intransportation fuels, vigorous scientific efforts have been devoted toresearch and development of hydrodesulfurization (HDS) catalysts [D.Kodjak, Policies to Reduce Fuel Consumption, Air Pollution, and CarbonEmissions from Vehicles in G20 Nations, 2015]. Catalyst designstrategies such as choosing suitable active metals (e.g. Co(Ni), Mo(W)),and selecting an appropriate metal support (e.g. alumina, silica,zeolites) are crucial for the development of efficient HDS catalysts.Adopting an effective synthesis method for preparing HDS catalysts isanother major factor impacting the efficiency and cost of catalysts [A.Bodin, A. L. N. Christoffersen, C. F. Elkjær, M. Brorson, J. Kibsgaard,S. Helveg, I. Chorkendorff, Nano Lett. 18 (2018) 3454-3460; and A.Mansouri, N. Semagina, ACS Appl. Nano Mater. 1 (2018) 4408-4412].

Over the years, various synthesis strategies for enhancing metaldispersion on catalyst support have been reported [J. Liang, M. Wu, P.Wei, J. Zhao, H. Huang, C. Li, Y. Lu, Y. Liu, C. Liu, J. Catal. 358(2018) 155-167; A. N. Varakin, A. V. Mozhaev, A. A. Pimerzin, P. A.Nikuishin, Appl. Catal. B Environ. 238 (2018) 498-508; and W. Song, W.Lai, Z. Chen, J. Cao, H. Wang, Y. Lian, W. Yang, X. Jiang, ACS Appl.Nano Mater. 1 (2018) 442-454, each incorporated herein by reference intheir entirety]. Different approaches for increasing formation of theactive MoS₂ phase and inhibiting sulfidation of the metal promoters,including the use of chelating agents, have been tested [L. van Haandel,G. M. Bremmer, E. J. M. Hensen, T. Weber, J. Catal. 351 (2017) 95-106;J. A. Toledo-Antonio, M. A. Cortes-Jacome, J. Escobar-Aguilar, C.Angeles-Chavez, J. Navarrete-Bolaños, E. López-Salinas, Appl. Catal. BEnviron. 213 (2017) 106-117; J. Escobar, M. C. Barrera, A. W. Gutiérrez,J. E. Terrazas, Fuel Process. Technol. 156 (2017) 33-42; and C. E.Santolalla-Vargas, V. Santes, C. Ortega-Niño, A. Hernández-Gordillo, F.Sanchez-Minero, L. Lartundo-Rojas, R. Borja-Urby, J. C. López-Curiel, O.Goiz, I. I. Padilla-Martinez, Catal. Today (2018), each incorporatedherein by reference in their entirety]. Recently, a single-pot strategythat involves subjecting a mixture containing both the supportprecursors and active metals precursors to hydrothermal treatment wasreported. It was demonstrated that this single-pot strategy couldenhance metal dispersion and formation of the MoS₂ phase [S. A. Ganiyu,K. Alhooshani, S. A. Ali, Appl. Catal. B Environ. 203 (2017) 428-441,incorporated herein by reference in its entirety].

In general, conventional synthesis approaches produce catalysts havingmetals in oxide forms. Therefore, an activation step that involvesreduction of the oxides and subsequent sulfidation is required.Furthermore, the reduction and sulfidation step is often incomplete dueto metal-support interactions [J. Jiao, J. Fu, Y. Wei, Z. Zhao, A. Duan,C. Xu, J. Li, H. Song, P. Zheng, X. Wang, Y. Yang, Y. Liu, J. Catal. 356(2017) 269-282, incorporated herein by reference in its entirety].

In view of the forgoing, one objective of the present disclosure is toprovide a straightforward method of producing a hydrodesulfurizationcatalyst having cobalt and molybdenum sulfide supported by mesoporoussilica without an additional sulfidation step or pre-treatment withsulfur. Another objective of the present disclosure is to provide aprocess of desulfurizing a hydrocarbon feedstock catalyzed by thehydrodesulfurization catalyst.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the present disclosure relates to a methodof preparing a CoMoS hydrodesulfurization catalyst comprising cobalt andmolybdenum sulfide disposed on a support material comprising amesoporous silica. The method involves the steps of (i) mixing amolybdenum precursor, a cobalt precursor, amercaptoalkyltrialkoxysilane, a structural directing surfactant, anacid, and a solvent to form a reaction mixture, (ii) hydrothermallytreating the reaction mixture to form a dried mass, and (iii) calciningthe dried mass in an activation gas, thereby forming the CoMoShydrodesulfurization catalyst, wherein the activation gas is at leastone selected from the group consisting of air, argon, nitrogen, helium,hydrogen, and carbon monoxide.

In one embodiment, the CoMoS hydrodesulfurization catalyst is notsubjected to a sulfidation with a sulfidation reagent.

In one embodiment, the mercaptoalkyltrialkoxysilane is at least oneselected from the group consisting of (mercaptomethyl)trimethoxysilane,(mercaptomethyl)triethoxysilane, (mercaptomethyl)tripropoxysilane,(2-mercaptoethyl)trimethoxysilane, (2-mercaptoethyl)triethoxysilane,(2-mercaptoethyl)tripropoxysilane, (3-mercaptopropyl)trimethoxysilane,(3-mercaptopropyl)triethoxysilane, and(3-mercaptopropyl)tripropoxysilane.

In one embodiment, the mercaptoalkyltrialkoxysilane is(3-mercaptopropyl)trimethoxysilane.

In one embodiment, the activation gas is argon, hydrogen, or both.

In one embodiment, the activation gas is hydrogen.

In one embodiment, the structural directing surfactant is P123.

In one embodiment, the acid is hydrochloric acid.

In one embodiment, the solvent is water.

In one embodiment, the reaction mixture is hydrothermally treated at atemperature of 60-150° C.

In one embodiment, the dried mass is calcined in the activation gas at atemperature of 250-600° C.

In one embodiment, the dried mass is calcined in the activation gas for0.5-8 hours.

In one embodiment, the mercaptoalkyltrialkoxysilane is present in thereaction mixture in an amount of 10-200 g per liter of the reactionmixture.

In one embodiment, the CoMoS hydrodesulfurization catalyst has a Mocontent in a range of 2-10% by weight relative to a total weight of thehydrodesulfurization catalyst.

In one embodiment, the CoMoS hydrodesulfurization catalyst has a Cocontent in a range of 0.02-0.2% by weight relative to a total weight ofthe hydrodesulfurization catalyst.

In one embodiment, the CoMoS hydrodesulfurization catalyst has a Scontent in a range of 0.5-5% by weight relative to a total weight of thehydrodesulfurization catalyst.

In one embodiment, the activation gas is hydrogen, argon, or both, andthe CoMoS hydrodesulfurization catalyst has a BET surface area of 80-400m²/g.

In one embodiment, the activation gas is hydrogen, argon, or both, andthe CoMoS hydrodesulfurization catalyst has a total pore volume of0.09-0.4 cm³/g, and an average pore size of 3-9 nm.

According to a second aspect, the present disclosure relates to a methodfor desulfurizing a hydrocarbon feedstock comprising a sulfur-containingcompound. The method involves contacting the hydrocarbon feedstock witha CoMoS hydrodesulfurization catalyst in the presence of H₂ gas toconvert at least a portion of the sulfur-containing compound into amixture of H₂S and a desulfurized product, and removing H₂S from themixture, thereby forming a desulfurized hydrocarbon stream, wherein (i)the CoMoS hydrodesulfurization catalyst comprises cobalt and molybdenumsulfide disposed on a support material comprising a mesoporous silica,(ii) the CoMoS hydrodesulfurization catalyst has a Mo content in a rangeof 2-10% by weight, a Co content in a range of 0.02-0.2% by weight, anda S content in a range of 0.5-5% by weight, each relative to a totalweight of the CoMoS hydrodesulfurization catalyst, (iii) the CoMoShydrodesulfurization catalyst has a BET surface area of 80-400 m²/g, atotal pore volume of 0.09-0.4 cm³/g, and an average pore size of 3-9 nm,and (iv) the CoMoS hydrodesulfurization catalyst is not sulfided priorto the contacting.

In one embodiment, the hydrocarbon feedstock is contacted with the CoMoShydrodesulfurization catalyst at a pressure of 2-10 MPa for 0.1-10hours, and the sulfur content of the desulfurized hydrocarbon stream is70-99% by weight less than that of the hydrocarbon feedstock.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a schematic illustration showing the synthesis of CoMoShydrodesulfurization catalysts.

FIG. 2A is an overlay of N₂ adsorption-desorption isotherms of CoMoShydrodesulfurization catalysts activated by air, argon, and hydrogen,respectively.

FIG. 2B is a graph showing pore size distributions of CoMoShydrodesulfurization catalysts activated by air, argon, and hydrogen,respectively.

FIG. 3A is an overlay of FTIR spectra of CoMoS hydrodesulfurizationcatalysts activated by air, argon, and hydrogen, respectively.

FIG. 3B is an overlay of X-ray diffraction (XRD) patterns of CoMoShydrodesulfurization catalysts activated by air, argon, and hydrogen,respectively.

FIG. 4A is a scanning electron microscope (SEM) image of CoMoShydrodesulfurization catalyst activated by air.

FIG. 4B is a SEM image of CoMoS hydrodesulfurization catalyst activatedby argon.

FIG. 4C is a SEM image of CoMoS hydrodesulfurization catalyst activatedby hydrogen.

FIG. 5A is an elemental mapping of carbon of CoMoS hydrodesulfurizationcatalyst activated by hydrogen.

FIG. 5B is an elemental mapping of oxygen of CoMoS hydrodesulfurizationcatalyst activated by hydrogen.

FIG. 5C is an elemental mapping of silicon of CoMoS hydrodesulfurizationcatalyst activated by hydrogen.

FIG. 5D is an elemental mapping of sulfur of CoMoS hydrodesulfurizationcatalyst activated by hydrogen.

FIG. 5E is an elemental mapping of cobalt of CoMoS hydrodesulfurizationcatalyst activated by hydrogen.

FIG. 5F is an elemental mapping of molybdenum of CoMoShydrodesulfurization catalyst activated by hydrogen.

FIG. 6A is an elemental mapping of carbon of CoMoS hydrodesulfurizationcatalyst activated by air.

FIG. 6B is an elemental mapping of oxygen of CoMoS hydrodesulfurizationcatalyst activated by air.

FIG. 6C is an elemental mapping of silicon of CoMoS hydrodesulfurizationcatalyst activated by air.

FIG. 6D is an elemental mapping of sulfur of CoMoS hydrodesulfurizationcatalyst activated by air.

FIG. 6E is an elemental mapping of cobalt of CoMoS hydrodesulfurizationcatalyst activated by air.

FIG. 6F is an elemental mapping of molybdenum of CoMoShydrodesulfurization catalyst activated by air.

FIG. 7A is an elemental mapping of carbon of CoMoS hydrodesulfurizationcatalyst activated by argon.

FIG. 7B is an elemental mapping of oxygen of CoMoS hydrodesulfurizationcatalyst activated by argon.

FIG. 7C is an elemental mapping of silicon of CoMoS hydrodesulfurizationcatalyst activated by argon.

FIG. 7D is an elemental mapping of sulfur of CoMoS hydrodesulfurizationcatalyst activated by argon.

FIG. 7E is an elemental mapping of cobalt of CoMoS hydrodesulfurizationcatalyst activated by argon.

FIG. 7F is an elemental mapping of molybdenum of CoMoShydrodesulfurization catalyst activated by argon.

FIG. 8A represents X-ray photoelectron spectroscopy (XPS) spectrashowing Mo phases of CoMoS hydrodesulfurization catalyst activated byair.

FIG. 8B represents XPS spectra showing Mo phases of CoMoShydrodesulfurization catalyst activated by argon.

FIG. 8C represents XPS spectra showing Mo phases of CoMoShydrodesulfurization catalyst activated by hydrogen.

FIG. 8D represents X-ray photoelectron spectroscopy (XPS) spectrashowing sulfide states of CoMoS hydrodesulfurization catalyst activatedby air.

FIG. 8E represents XPS spectra showing sulfide states of CoMoShydrodesulfurization catalyst activated by argon.

FIG. 8F represents XPS spectra showing sulfide states of CoMoShydrodesulfurization catalyst activated by hydrogen.

FIG. 9 is a plot summarizing hydrodesulfurization catalytic activitiesof CoMoS hydrodesulfurization catalysts activated by air, argon, andhydrogen, respectively.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will now be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all embodiments of the disclosure are shown.

As used herein, the words “a” and “an” and the like carry the meaning of“one or more”. Within the description of this disclosure, where anumerical limit or range is stated, the endpoints are included unlessstated otherwise. Also, all values and subranges within a numericallimit or range are specifically included as if explicitly written out.

As used herein, “compound” and “precursor” are intended to refer to achemical entity, whether as a solid, liquid, or gas, and whether in acrude mixture or isolated and purified.

The present disclosure includes all hydration states of a given salt orformula, unless otherwise noted. For example, cobalt(II) nitrateincludes anhydrous Co(NO₃)₂, hexahydrate Co(NO₃)₂.6H₂O, and any otherhydrated forms or mixtures. Ammonium heptamolybdate(VI) includesanhydrous (NH₄)₆MoO₂₄, and hydrated forms such as ammoniumheptamolybdate tetrahydrate (NH₄)₆Mo₇O₂₄.4H₂O.

As used herein, the term “alkyl” unless otherwise specified refers toboth branched and straight chain saturated aliphatic primary, secondary,and/or tertiary hydrocarbon fragments of typically C₁ to C₂₀.Non-limiting examples of such hydrocarbon fragments include methyl,trifluoromethyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl,t-butyl, pentyl, cyclopentyl, isopentyl, neopentyl, hexyl, isohexyl,cyclohexyl, cyclohexylmethyl, 3-methylpentyl, 2,2-dimethylbutyl,2,3-dimethylbutyl, 2-ethylhexyl, heptyl, octyl, nonyl,3,7-dimethyloctyl, decyl, undecyl, dodecyl, tridecyl, 2-propylheptyl,tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl, nonadecyl, andeicosyl. As used herein, the term optionally includes substituted alkylgroups. Exemplary moieties with which the alkyl group can be substitutedmay be selected from the group including, but not limited to, hydroxy,amino, alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonicacid, sulfate, phosphonic acid, phosphate, halo, or phosphonate ormixtures thereof. The substituted moiety may be either protected orunprotected as necessary, and as known to those of ordinary skill in theart.

The term “alkoxy” refers to a straight or branched chain alkoxyincluding, but not limited to, methoxy, ethoxy, propoxy, isopropoxy,butoxy, isobutoxy, secondary butoxy, tertiary butoxy, pentoxy,isopentoxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy.

The present disclosure is intended to include all isotopes of atomsoccurring in the present compounds. Isotopes include those atoms havingthe same atomic number but different mass numbers. By way of generalexample, and without limitation, isotopes of hydrogen include deuteriumand tritium, isotopes of carbon include ¹²C, ¹³C, and ¹⁴C, isotopes ofoxygen include ¹⁶O, ¹⁷, and ¹⁸O, and isotopes of molybdenum include⁹²Mo, ⁹⁴⁻⁹⁸Mo, and ¹⁰⁰Mo. Isotopically labeled compounds of thedisclosure can generally be prepared by conventional techniques known tothose skilled in the art or by processes and methods analogous to thosedescribed herein, using an appropriate isotopically labeled reagent inplace of the non-labeled reagent otherwise employed.

According to a first aspect, the present disclosure relates to a methodof preparing a CoMoS hydrodesulfurization catalyst comprising cobalt andmolybdenum sulfide disposed on a support material comprising amesoporous silica. The method involves the steps of (i) mixing amolybdenum precursor, a cobalt precursor, amercaptoalkyltrialkoxysilane, a structural directing surfactant, anacid, and a solvent to form a reaction mixture, (ii) hydrothermallytreating the reaction mixture to form a dried mass, and (iii) calciningthe dried mass in an activation gas, thereby forming the CoMoShydrodesulfurization catalyst, wherein the activation gas is at leastone selected from the group consisting of air, argon, and hydrogen.

The use of thiosalts, both as active metals and sulfur precursors, hasbeen demonstrated as a more straightforward and reproducible approachthan reduction and sulfidation of the metal oxide catalysts [G.Alonso-Núñez, J. Bocarando, R. Huirache-Acuña, L. Alvarez-Contreras, Z.D. Huang, W. Bensch, G. Berhault, J. Cruz, T. A. Zepeda, S. Fuentes,Appl. Catal. A Gen. 419-420 (2012) 95-101; and Y. Yi, C. T. Williams, M.Glascock, G. Xiong, J. Lauterbach, C. Liang, Mater. Res. Bull. 56 (2014)54-64, each incorporated herein by reference in their entirety]. Thisapproach has been utilized to produce unsupported active catalystshaving stoichiometric amounts of bi- and tri-metallic sulfides viathermal decomposition of the thiosalt [Y. Yi, B. Zhang, X. Jin, L. Wang,C. T. Williams, G. Xiong, D. Su, C. Liang, J. Mol. Catal. A Chem. 351(2011) 120-127; and R. Huirache-Acuña, G. Alonso-Núñez, F.Paraguay-Delgado, J. Lara-Romero, G. Berhault, E. M. Rivera-Muñoz,Catal. Today 250 (2015) 28-37]. A series of tungsten disulfides (WS₂) asHDS catalysts have been prepared by thermal decomposition of ammoniumtetrathiotungstates and tetraalkylammonium thiotunstate under the flowof N₂ and H₂S/H₂, respectively [R. Romero-Rivera, G. Berhault, G.Alonso-Núñez, M. Del Valle, F. Paraguay-Delgado, S. Fuentes, S. Salazar,A. Aguilar, J. Cruz-Reyes, Appl. Catal. A Gen. 433-434 (2012) 115-121,incorporated herein by reference in its entirety]. Romero et al.synthesized MoS₂ catalysts using various alkyldiammonium thiomolybdateprecursors (alkyl=ethyl, 1,4-butyl, 1,6-hexyl and 1,8-octyl). Due todecomposition of the alkyl chains present in the precursors, carbon wasobserved to be intercalated within the pores of the MoS₂ catalysts [L.Romero, M. Del Valle, R. Romero-Rivera, G. Alonso, M. Avalos-Borja, S.Fuentes, F. Paraguay-Delgado, J. Cruz-Reyes, Catal. Today 250 (2015)66-71, incorporated herein by reference in its entirety]. Ammonium andalkyltrimethylammonium-thiomolybdate-thiotungstate-cobaltate(II) wereused as precursors to prepare various CoMoW—S catalysts for HDS ofdibenzothiophene (DBT) via thermal decomposition Y. Espinoza-Armenta, J.Cruz-Reyes, F. Paraguay-Delgado, M. Del Valle, G. Alonso, S. Fuentes, R.Romero-Rivera, Appl. Catal. A Gen. 486 (2014) 62-68, incorporated hereinby reference in its entirety]. The use of thiosalts is a particularlysuccessful strategy in the synthesis of unsupported bulk HDS catalystswith a low surface area. However, this approach can be complicated andchallenging because the thiosalt and metal precursors are oftensynthesized separately prior to the in situ/ex situ decomposition.

The method of the present disclosure uses a silica source that is asulfur-containing silane such as a mercaptoalkyltrialkoxysilane havingformula (I)

where (i) R₁, R₂, and R₃ are each independently an optionallysubstituted alkoxy, preferably an optionally substituted C₁-C₂₂ alkoxy,preferably an optionally substituted C₂-C₂₀ alkoxy, preferably anoptionally substituted C₃-C₁₈ alkoxy, preferably an optionallysubstituted C₄-C₁₆ alkoxy, preferably an optionally substituted C₅-C₁₄alkoxy, preferably an optionally substituted C₆-C₁₂ alkoxy, preferablyan optionally substituted C₇-C₁₀ alkoxy, preferably an optionallysubstituted C₈-C₉ alkoxy, (ii) R₄ and R₅ are each independently ahydrogen, or an optionally substituted C₁-C₆ alkyl, preferably ahydrogen, and (iii) m is an integer ranging from 1-8, preferably 2-7,preferably 3-6, preferably 4-5; and a mercaptoalkyldialkoxysilane havingformula (II)

where (i) R₆ and R₇ are each independently an optionally substitutedalkoxy, preferably an optionally substituted C₁-C₂₂ alkoxy, preferablyan optionally substituted C₂-C₂₀ alkoxy, preferably an optionallysubstituted C₃-C₁₈ alkoxy, preferably an optionally substituted C₄-C₁₆alkoxy, preferably an optionally substituted C₅-C₁₄ alkoxy, preferablyan optionally substituted C₆-C₁₂ alkoxy, preferably an optionallysubstituted C₇-C₁₀ alkoxy, preferably an optionally substituted C₈-C₉alkoxy, (ii) R₈ is an optionally substituted C₁-C₂₂ alkyl, preferably anoptionally substituted C₂-C₂₀ alkyl, preferably an optionallysubstituted C₃-C₁₈ alkyl, preferably an optionally substituted C₄-C₁₆alkyl, preferably an optionally substituted C₅-C₁₄ alkyl, preferably anoptionally substituted C₆-C₁₂ alkyl, preferably an optionallysubstituted C₇-C₁₀ alkyl, preferably an optionally substituted C₆-C₁₂alkyl, (iii) R₉ and R₁₀ are each independently a hydrogen, or anoptionally substituted C₁-C₆ alkyl, preferably a hydrogen, and (iv) n isan integer ranging from 1-8, preferably 2-7, preferably 3-6, preferably4-5.

Exemplary sulfur-containing silanes include, but are not limited to,(3-mercaptopropyl)trimethoxysilane, (3-mercaptopropyl)triethoxysilane,(3-mercaptopropyl)diethoxymethoxysilane,(3-mercaptopropyl)tripropoxysilane,(3-mercaptopropyl)dipropoxymethoxysilane,(3-mercaptopropyl)tridodecanoxysilane,(3-mercaptopropyl)tritetradecanoxysilane,(3-mercaptopropyl)trihexadecanoxysilane,(3-mercaptopropyl)trioctadecanoxysilane(3-mercaptopropyl)didodecanoxytetradecanoxysilane,(3-mercaptopropyl)dodecanoxytetradecanoxyhexadecanoxysilane,(3-mercaptopropyl)dimethoxymethylsilane,(3-mercaptopropyl)diethoxymethylsilane,(3-mercaptopropyl)dipropoxymethylsilane,(3-mercaptopropyl)diisopropoxymethylsilane,(3-mercaptopropyl)dibutoxymethylsilane,(3-mercaptopropyl)diisobutoxymethylsilane,(3-mercaptopropyl)didodecanoxymethylsilane,(3-mercaptopropyl)ditetradecanoxymethylsilane,(2-mercaptoethyl)trimethoxysilane, (2-mercaptoethyl)triethoxysilane,(2-mercaptoethyl)diethoxymethoxysilane,(2-mercaptoethyl)tripropoxysilane,(2-mercaptoethyl)dipropoxymethoxysilane.(2-mercaptoethyl)tridodecanoxysilane,(2-mercaptoethyl)tritetradecanoxysilane,(2-mercaptoethyl)trihexadecanoxysilane,(2-mercaptoethyl)trioctadecanoxysilane,(2-mercaptoethyl)didodecanoxytetradecanoxysilane,(2-mercaptoethyl)dodecanoxytetradecanoxyhexadecanoxysilane,(2-mercaptoethyl)dimethoxymethylsilane,(2-mercaptoethyl)diethoxymethylsilane, (mercaptomethyl)trimethoxysilane,(mercaptomethyl)triethoxysilane, (mercaptomethyl)diethoxymethoxysilane,(mercaptomethyl)dipropoxymethoxysilane,(mercaptomethyl)tripropoxysilane, (mercaptomethyl)trimethoxysilane,(mercaptomethyl)dimethoxymethylsilane,(mercaptomethyl)diethoxymethylsilane, (3-mercaptobutyl)trimethoxysilane,(3-mercaptobutyl)triethoxysilane,(3-mercaptobutyl)diethoxymethoxysilane,(3-mercaptobutyl)tripropoxysilane,(3-mercaptobutyl)dipropoxymethoxysilane,(3-mercaptobutyl)dimethoxymethylsilane,(3-mercaptobutyl)diethoxymethylsilane,(3-mercaptobutyl)tridodecanoxysilane,(3-mercaptobutyl)tritetradecanoxysilane,(3-mercaptobutyl)trihexadecanoxysilane,(3-mercaptobutyl)didodecanoxytetradecanoxysilane,(3-mercaptobutyl)dodecanoxytetradecanoxyhexadecanoxysilane,(3-mercapto-2-methyl-propyl)trimethoxysilane,(3-mercapto-2-methyl-propyl)triethoxysilane,(3-mercapto-2-methyl-propyl)diethoxymethoxysilane,(3-mercapto-2-methyl-propyl)tripropoxysilane,(3-mercapto-2-methyl-propyl)dipropoxymethoxysilane,(3-mercapto-2-methyl-propyl)tridodecanoxysilane,(3-mercapto-2-methyl-propyl)tritetradecanoxysilane,(3-mercapto-2-methyl-propyl)trihexadecanoxysilane,(3-mercapto-2-methyl-propyl)trioctadecanoxysilane,(3-mercapto-2-methyl-propyl)didodecanoxytetradecanoxysilane,(3-mercapto-2-methyl-propyl)dodecanoxytetradecanoxyhexadecanoxysilane,(3-mercapto-2-methyl-propyl)dimethoxymethylsilane,(3-mercapto-2-methyl-propyl)diethoxymethylsilane,(3-mercapto-2-methyl-propyl)dipropoxymethylsilane,(3-mercapto-2-methyl-propyl)diisopropoxymethylsilane,(3-mercapto-2-methyl-propyl)dibutoxymethylsilane,(3-mercapto-2-methyl-propyl)disiobutoxymethylsilane,(3-mercapto-2-methyl-propyl)didodecanoxymethylsilane, and(3-mercapto-2-methyl-propyl)ditetradecanoxymethylsilane.

In one or more embodiment, the method of the present disclosure uses amercaptoalkyltrialkoxysilane which is at least one selected from thegroup consisting of (mercaptomethyl)trimethoxysilane,(mercaptomethyl)triethoxysilane, (mercaptomethyl)tripropoxysilane,(2-mercaptoethyl)trimethoxysilane, (2-mercaptoethyl)triethoxysilane,(2-mercaptoethyl)tripropoxysilane, (3-mercaptopropyl)trimethoxysilane(MPMS), (3-mercaptopropyl)triethoxysilane, and(3-mercaptopropyl)tripropoxysilane. In a preferred embodiment, themercaptoalkyltrialkoxysilane is (3-mercaptopropyl)trimethoxysilane,(3-mercaptopropyl)triethoxysilane, (3-mercaptopropyl)tripropoxysilane,or mixtures thereof. Most preferably, the mercaptoalkyltrialkoxysilaneis (3-mercaptopropyl)trimethoxysilane.

In one or more embodiments, the structural directing surfactant is anonionic block copolymer. A block copolymer is a type of copolymer madeup of blocks of different polymerized monomers. In a block copolymer, aportion of the macromolecule comprising many constitutional units has atleast one feature which is not present in the adjacent portions. Blockcopolymers preferably comprise two or more homopolymer and/orhomooligomer subunits linked by covalent bonds. The union of thehomopolymer subunits may require an intermediate non-repeating subunit,known as a junction block. Block copolymers with two or three distinctblocks are called diblock copolymers and triblock copolymersrespectively, tetrablocks, and multiblocks, etc. may also be fabricated.In stereoblock copolymers, a special structure may be formed from onemonomer where the distinguishing feature is the tacticity of each block.The structural directing surfactant may be a block copolymer, astereoblock copolymer, or mixtures thereof.

In one embodiment, the structural directing surfactant is a poloxamer.Poloxamers are nonionic triblock copolymers composed of a centralhydrophobic chain of polyoxypropylene (poly(propylene oxide), or PPO)flanked by two hydrophilic chains of polyoxyethylene (poly(ethyleneoxide), or PEO). Because the lengths of the polymer blocks may becustomized, many different poloxamers that have slightly differentproperties exist. For the generic term poloxamer, these copolymers arecommonly named with the letter P (for poloxamer) followed by threedigits: the first two digits multiplied by 100 give the approximatemolecular mass of the polyoxypropylene core in g/mol, and the last digitmultiplied by 10 gives the percentage polyoxyethylene content. In oneembodiment, the structural directing surfactant is P123 poloxamer (i.e.P123), which is a symmetric triblock copolymer comprising poly(ethyleneoxide) (PEO) and poly(propylene oxide) (PPO) in an alternating linearfashion, PEO-PPO-PEO. The unique characteristic of PPO block, which ishydrophobic at temperatures above 288 K and is soluble in water attemperatures below 288 K, leads to the formation of micelles comprisingPEO-PPO-PEO triblock copolymers. The nominal chemical formula of P123 isHO(CH₂CH₂O)₂₀(CH₂CH(CH₃)O)₇₀(CH₂CH₂O)₂₀H, which corresponds to amolecular weight of around 5,800 g/mol. P123 poloxamer may be known bythe trade name Pluronic® P-123.

The acid may be an inorganic or organic acid such as hydrochloric acid,formic acid, benzoic acid, acetic acid, phosphoric acid, hydrobromicacid, hydroiodic acid, nitric acid, hydrofluoric acid, sulfuric acid,and/or perchloric acid or some other acid. In a preferred embodiment,the acid is hydrochloric acid, nitric acid, hydrofluoric acid, sulfuricacid, and/or perchloric acid. Most preferably, the acid is hydrochloricacid (HC).

In one or more embodiment, the molybdenum precursor is a Mo(VI) salt.Exemplary Mo(VI) salts include, but are not limited to, ammoniumheptamolybdate(VI), ammonium heptamolybdate(VI) tetrahydrate, ammoniummolybdate(VI), ammonium phosphomolybdate, ammonium tetrathiomolybdate,sodium molybdate(VI), lithium molybdate(VI), molybdenum(VI) dichloridedioxide, and mixtures and hydrates thereof. In certain embodiments, amolybdenum salt having a different oxidation state, such as +2 (e.g.molybdenum(II) carboxylates), +3 (e.g. molybdenum(III) chloride), +4(e.g. molybdenum(IV) carbonate), and +5 (e.g. molybdenum(V) chloride),may be used in addition to or in lieu of the Mo(VI) salt. Alternatively,a molybdenum acid, a molybdenum base may be used in addition to or inlieu of the Mo(VI) salt. In a preferred embodiment, ammoniumheptamolybdate(VI) tetrahydrate is used as the molybdenum precursor.

In one or more embodiments, the cobalt precursor is a Co(I) salt.Exemplary Co(II) salts include, but are not limited to, cobalt(II)nitrate, cobalt(II) nitrate hexahydrate, cobalt(II) chloride, cobalt(II)chloride hexahydrate, cobalt(II) acetate, cobalt(II) sulfate, cobalt(II)bromide, cobalt(II) iodide, and mixtures and hydrates thereof. Incertain embodiments, a cobalt salt having a different oxidation state,such as +3 (e.g. cobalt(Ill) fluoride), +5 (e.g. potassiumpercobaltate), may be used in addition to or in lieu of the Co(II) salt.In a preferred embodiment, cobalt(II) chloride hexahydrate is used asthe cobalt precursor.

The sulfur-containing silane (e.g. mercaptoalkyltrialkoxysilane), thestructural directing surfactant, the acid, and the molybdenum and thecobalt precursors may be mixed with solvent to form a reaction mixture.The solvent may be water, an alcohol such as methanol and ethanol, or amixture thereof. In one or more embodiments, the solvent is water,preferably deionized or distilled water. The reaction mixture maycomprise 1-15 wt %, preferably 2-10 wt %, preferably 4-8 wt %,preferably 5-7 wt % of the acid relative to a total weight of thereaction mixture.

Prior to the mixing step, the sulfur-containing silane (e.g.mercaptoalkyltrialkoxysilane), the structural directing surfactant, andthe acid may be combined in the solvent to form a siliceous mixture,which is stirred for 0.1-12 hours, preferably 0.5-8 hours, preferably1-4 hours, or about 2 hours, and then mixed with the molybdenum and thecobalt precursors for 1-48 hours, preferably 5-36 hours, preferably10-24 hours, or about 20 hours to form the reaction mixture. In analternative embodiment, the aforementioned reagents (i.e. thesulfur-containing silane, the structural directing surfactant, the acid,the molybdenum and the cobalt precursors) are mixed in the solvent for2-50 hours, 5-40 hours, or 10-24 hours to form the reaction mixture.

Mixings may occur via stirring, shaking, swirling, sonicating, blending,or by otherwise agitating a mixture. In one embodiment, the mixture isstirred by a magnetic stirrer or an overhead stirrer. In anotherembodiment, the mixture is left to stand (i.e. not stirred).Alternatively, the mixture is subjected to ultrasonication. Theultrasonication may be performed using an ultrasonic bath or anultrasonic probe.

The structural directing surfactant may be present in the reactionmixture in an amount of 5-75 g, preferably 10-50 g, more preferably20-30 g per liter of the reaction mixture. The sulfur-containing silane(e.g. mercaptoalkyltrialkoxysilane) may be present in the reactionmixture in an amount of 10-200 g, preferably 25-150 g, more preferably50-100 g per liter of the reaction mixture. In one embodiment, thereaction mixture has a Mo:Co weight ratio of 1:1 to 8:1, preferably 2:1to 6:1, more preferably 3:1 to 5:1, or about 3.3:1. In some embodiments,the cobalt precursor is present in the reaction mixture in an amount of1.5-6 wt %, preferably 2-4 wt %, more preferably about 3 wt % relativeto a total weight of the reaction mixture. In a related embodiment, themolybdenum precursor is present in the reaction mixture in an amount of6-20 wt %, preferably 8-15 wt %, more preferably about 10 wt % relativeto a total weight of the reaction mixture.

The reaction mixture may be hydrothermally treated to form a dried mass.In one embodiment, the reaction mixture is hydrothermally treated viaheating in an autoclave at 50-150° C., preferably 60-120° C., morepreferably 70-100° C., or about 90° C. for 6-48 hours, preferably 12-36hours, more preferably 18-24 hours to produce a reaction mass. Anexternal heat source, such as an oven, a heating mantle, a water bath,or an oil bath, may be employed to dry the reaction mass of the presentdisclosure. Alternatively, the reaction mass may be air dried. Thereaction mass may be dried, for instance, in an oven at a temperature of80-120° C., preferably 85-110° C., more preferably 90-105° C., or about100° C. for 3-36 hours, preferably 6-24 hours, or about 12 hours to forma dried mass. In one embodiment, the reaction mass is dried via heatingin air. Alternatively, the reaction mass is dried in oxygen-enrichedair, an inert gas, or a vacuum.

The dried mass is preferably formed via an one-pot strategy. As usedherein, the terms “one-pot” and “single-pot” refer to a processingapproach whereby starting materials of the CoMoS hydrodesulfurizationcatalyst, i.e. the sulfur-containing silane, the structural directingsurfactant, the acid, the molybdenum and the cobalt precursors are mixedand undergo physical/chemical transformations in a single container(e.g. a single reactor, a single vessel).

The dried mass may be calcined in an atmosphere containing an activationgas to form a CoMoS hydrodesulfurization catalyst. In one or moreembodiments, the activation gas present in the atmosphere is a reducinggas such as hydrogen gas (H₂), carbon monoxide (CO), and ammonia gas, aninert gas such as argon (Ar), nitrogen (N₂), and helium (He), and/orair. In a preferred embodiment, the activation gas is a reducing gassuch as hydrogen. In another preferred embodiment, the activation gas isan inert gas such as argon. In one embodiment, the activation gas is amixture of a reducing gas and an inert gas. Most preferably, theactivation gas is hydrogen. When a reducing gas is used as theactivation gas, the atmosphere may contain 5-99%, preferably 10-80%,more preferably 20-50% by volume of the reducing gas (e.g. H₂) dilutedin nitrogen, helium, and/or argon relative to a total volume of theatmosphere. The atmosphere containing the activation gas (e.g. hydrogen,argon gas, air) may stay stagnant over the dried mass. Alternatively,the atmosphere containing the activation gas is passed through the driedmass. In one embodiment, the atmosphere containing the activation gas ispassed through the dried mass at a flow rate of 1-1,000 mL/min, 10-750mL/min, 50-500 mL/min, or 100-250 ml/min.

Preferably, the dried mass is calcined in the atmosphere containing theactivation gas at a temperature in a range of 200-600° C., preferably250-550° C., preferably 300-500° C., preferably 350-450° C., or about400° C. for 0.5-8 hours, preferably 1-6 hours, preferably 2-4 hours, orabout 3 hours to form the CoMoS hydrodesulfurization catalyst.Calcination can be carried out within shaft furnaces, rotary kilns,multiple hearth furnaces, and/or fluidized bed reactors.

Conventional hydrodesulfurization catalysts are often sulfided with asulfidation reagent (e.g. a sulfide-containing compound) at an elevatedtemperature, for example in a range of 250-500° C., or 300450° C., for aperiod of time, such as at least 1 hour, 2-10 hours, or 4-8 hours. Thesulfide-containing compound may be carbon disulfide (CS₂), dimethyldisulfide, ethylene sulfide, trimethylene sulfide, propylene sulfide,and bis(methylthio)methane. This additional sulfiding step may convertactive catalyst materials in oxide form to their corresponding sulfideform, which are catalytically more active than the oxide form.

It is worth noting that the method of the present disclosure does notinvolve a separate sulfidation process. The CoMoS hydrodesulfurizationcatalyst is formed via a single step procedure where sulfidation occurssimultaneously with calcination (i.e. single-step calcination andsulfidation). During the calcination in the presence of the activationgas, thiol groups on the sulfur-containing silane (e.g.mercaptoalkyltrialkoxysilane) may be decomposed to sulfide-containingcompounds such as hydrogen sulfide (H₂S). As a result, Mo oxides formedby calcining the dried mass may be simultaneously sulfided with thesulfide-containing compounds (e.g. H₂S) generated in-situ throughout thecalcination process. In most embodiments, the CoMoS hydrodesulfurizationcatalyst is not subjected to a sulfidation with a sulfidation reagent(e.g. a sulfide-containing compound). Instead, the CoMoShydrodesulfurization catalyst is obtained via the single-stepcalcination and sulfidation on the dried mass without isolation of Mooxides and additional sulfidation reagents. Adopting the one-potstrategy to form the dried mass and performing the single-stepcalcination and sulfidation on the dried mass may eliminate the numberof separation and purification steps, avoid the use of toxic sulfidationreagents, reduce operation time, improve product yield, and lowerpreparation cost.

In one or more embodiments, the CoMoS hydrodesulfurization catalystprepared by the method of the first aspect has cobalt and molybdenumsulfide disposed on a support material. In a preferred embodiment, thesupport material comprises a mesoporous silica. A “mesoporous support”refers to a porous support material with largest pore diameters rangingfrom about 2-50 nm, preferably 3-45 nm, preferably 4-40 nm, preferably5-25 nm. As used herein, “mesoporous silica” refers to a mesoporoussupport comprising silica (SiO₂). Non-limiting examples of mesoporoussilica include MCM-48, MCM-41, MCM-18, SBA-11, SBA-12, SBA-15, andSBA-16. In one or more embodiments, the support material has pores thatare microporous. The term “microporous” means the pores of the supportmaterial have an average diameter of less than 2 nm.

In one embodiment, the support material is mesoporous and has porechannels that are regularly arranged. For example, the mesoporoussupport material is in the form of a honeycomb-like structure havingpore channels parallel or substantially parallel to each other within atwo-dimensional hexagon (e.g. SBA-15). Alternatively, other mesoporoussilica structures of the SBA series such as SBA-11 having a cubicstructure, SBA-12 having a three-dimensional hexagonal structure, andSBA-16 having a cubic in cage-like structure may be used as themesoporous support material.

As used herein, “disposed on” describes catalytic materials beingdeposited on or impregnated in a support material such that the supportmaterial is completely or partially filled throughout, saturated,permeated, and/or infused with the catalytic materials. The catalyticmaterials (i.e. cobalt and molybdenum sulfide) may be affixed to supportmaterial (e.g. mesoporous silica) in any reasonable manner, such asphysisorption, chemisorption, or mixtures thereof. In a relatedembodiment, the CoMoS hydrodesulfurization catalyst of the presentdisclosure may have both cobalt and molybdenum sulfide decorated on thesurface of the support material (e.g. mesoporous silica). In anotherrelated embodiment, the CoMoS hydrodesulfurization catalyst may haveboth cobalt and molybdenum sulfide disposed on the surface andimpregnated in the support material.

In preferred embodiments, the cobalt and the molybdenum sulfide arehomogeneously distributed throughout the support material. The cobaltand molybdenum species and their distributions on the support materialmay be identified by techniques including, but not limited to, UV-visspectroscopy, XRD, Raman spectroscopy, AFM (atomic force microscope),TEM (transmission electron microscopy), and EPR (electron paramagneticresonance). In one embodiment, greater than 10% of the surface area(i.e. surface and pore spaces) of the support material (e.g. mesoporoussilica) is covered by the cobalt and the molybdenum sulfide, preferablygreater than 15%, preferably greater than 20%, preferably greater than25%, preferably greater than 30%, preferably greater than 35%,preferably greater than 40%, preferably greater than 45%, preferablygreater than 50%, preferably greater than 55%, preferably greater than60%, preferably greater than 65%, preferably greater than 70%,preferably greater than 75%, preferably greater than 80%, preferablygreater than 85%, preferably greater than 90%, preferably greater than95%, preferably greater than 96%, preferably greater than 97%,preferably greater than 98%, preferably greater than 99% of the supportmaterial is covered by the cobalt and the molybdenum sulfide.

In one or more embodiments, the CoMoS hydrodesulfurization catalystdisclosed herein has a Mo content in a range of 2-10%, preferably 3-9%,preferably 4-8%, preferably 5-7%, or about 6% by weight relative to atotal weight of the CoMoS hydrodesulfurization catalyst. However, incertain embodiments, the CoMoS hydrodesulfurization catalyst has a Mocontent that is less than 2% or greater than 10% by weight relative to atotal weight of the CoMoS hydrodesulfurization catalyst. Preferably,molybdenum is present in the CoMoS hydrodesulfurization catalyst insulfide forms (e.g. MoS₂, MoS₃). However, in certain embodiments,molybdenum may be present in other species such as metallic molybdenumand oxide forms (e.g. MoO₂, MoO₃) in the CoMoS hydrodesulfurizationcatalyst in addition to molybdenum sulfides.

In one or more embodiments, the CoMoS hydrodesulfurization catalyst hasa Co content in a range of 0.02-0.2%, preferably 0.03-0.15%, preferably0.04-0.1%, preferably 0.05-0.08%, preferably 0.06-0.07% by weightrelative to a total weight of the CoMoS hydrodesulfurization catalyst.However, in certain embodiments, the CoMoS hydrodesulfurization catalysthas a Co content that is less than 0.02% or greater than 0.2% by weightrelative to a total weight of the CoMoS hydrodesulfurization catalyst.In a related embodiment, the CoMoS hydrodesulfurization catalyst has aMo:Co weight ratio of 200:1 to 10:1, preferably 150:1 to 25:1,preferably 120:1 to 50:1, preferably 110:1 to 70:1, preferably 100:1 to80:1. In certain embodiments, the CoMoS hydrodesulfurization catalysthas a Mo:Co weight ratio that is less than 10:1 or greater than 200:1.Preferably, cobalt is present in the CoMoS hydrodesulfurization catalystin its reduced form as metallic cobalt. However, in certain embodiments,cobalt may be present in other species such as sulfide forms (e.g. CoS,CoS₂, Co₃S₄, Co₉S₈) and oxide forms (e.g. CoO, Co₂O₃, Co₃O₄) in theCoMoS hydrodesulfurization catalyst in addition to metallic cobalt.

In one or more embodiments, the CoMoS hydrodesulfurization catalyst hasa S content in a range of 0.5-5%, preferably 0.9-4%, preferably 1-3%,preferably 1.2-2.5%, preferably 1.3-2%, preferably 1.5-1.9%, preferably1.6-1.8% by weight relative to a total weight of the CoMoShydrodesulfurization catalyst. In one embodiment, a CoMoShydrodesulfurization catalyst prepared by the presently disclosed methodusing hydrogen, argon, or both as the activation gas has a S contentthat is 30-75% greater, preferably 35-60% greater, more preferably40-55% greater than that of a CoMoS hydrodesulfurization catalystprepared using air as the activation gas. In a related embodiment, aCoMoS hydrodesulfurization catalyst prepared by the presently disclosedmethod using hydrogen as the activation gas has a S content that is35-70% greater, preferably 40-60% greater, more preferably 45-50%greater than that of a CoMoS hydrodesulfurization catalyst preparedusing argon as the activation gas.

An average diameter (e.g., average particle size) of the particle, asused herein, and unless otherwise specifically noted, refers to theaverage linear distance measured from one point on the particle throughthe center of the particle to a point directly across from it. For acircle, an oval, an ellipse, and a multilobe, the term “diameter” refersto the greatest possible distance measured from one point on the shapethrough the center of the shape to a point directly across from it. Forpolygonal shapes, the term “diameter”, as used herein, and unlessotherwise specified, refers to the greatest possible distance measuredfrom a vertex of a polygon through the center of the face to the vertexon the opposite side.

The CoMoS hydrodesulfurization catalyst may be in the form of particleswith an average diameter in a range of 0.1-50 μm, 1-40 μm, 5-20 μm, or10-15 μm. In one embodiment, the CoMoS hydrodesulfurization catalystparticles are monodisperse, having a coefficient of variation orrelative standard deviation, expressed as a percentage and defined asthe ratio of the particle diameter standard deviation (a) to theparticle diameter mean (p), multiplied by 100%, of less than 25%,preferably less than 10%, preferably less than 8%, preferably less than6%, preferably less than 5%. In one embodiment, the catalyst particlesare monodisperse having a particle size distribution ranging from 80% ofthe average particle size (e.g. diameter) to 120% of the averageparticle size, preferably 85-115%, preferably 90-110% of the averageparticle size. In another embodiment, the CoMoS hydrodesulfurizationcatalyst particles are not monodisperse.

The CoMoS hydrodesulfurization catalyst particles may be agglomerated ornon-agglomerated (i.e., the particles are well separated from oneanother and do not form clusters). In some embodiments, the CoMoShydrodesulfurization catalyst particles may cluster and formagglomerates having an average diameter in a range of 2-500 μm, 10-200μm, or 50-100 μm.

The CoMoS hydrodesulfurization catalyst of the present disclosure may besquare-shaped, triangle-shaped, rod-like, spherical, or substantiallyspherical (e.g., oval or oblong shape). In other embodiments, the CoMoShydrodesulfurization catalyst can be of any shape that provides desiredcatalytic activity and stability of the CoMoS hydrodesulfurizationcatalyst. For example, the CoMoS hydrodesulfurization catalyst may be ina form of at least one shape such as a triangle, a square, a sphere, arod, a disc, and a platelet. In one embodiment, the CoMoShydrodesulfurization catalyst of the present disclosure isirregular-shaped having sides and angles of unequal length and size (seeFIGS. 4A-C).

The Brunauer-Emmet-Teller (BET) theory (S. Brunauer, P. H. Emmett, E.Teller, J. Am. Chem. Soc. 1938, 60, 309-319, incorporated herein byreference) aims to explain the physical adsorption of gas molecules on asolid surface and serves as the basis for an important analysistechnique for the measurement of a specific surface area of a material.Specific surface area is a property of solids which is the total surfacearea of a material per unit of mass, solid or bulk volume, or crosssectional area. In most embodiments, pore size (i. e. pore diameter),total pore volume, and BET surface area are measured by gas adsorptionanalysis, preferably N₂ adsorption analysis (e.g. N₂ adsorptionisotherms).

In one or more embodiments, the CoMoS hydrodesulfurization catalyst hasa BET surface area of 10-500 m²/g, preferably 30-400 m²/g, preferably50-300 m²/g, preferably 75-250 m²/g, preferably 100-200 m²/g, preferably150-175 m²/g. In a preferred embodiment, when hydrogen, argon, or bothare used as the activation gas, the CoMoS hydrodesulfurization catalysthas a BET surface area of 80-500 m²/g, 100-400 m²/g, 150-300 m²/g, or200-250 m²/g. In another embodiment, when air is used as the activationgas, the CoMoS hydrodesulfurization catalyst has a BET surface area of10-50 m²/g, 20-40 m²/g, 25-35 m²/g, or about 30 m²/g. In at least oneembodiment, a CoMoS hydrodesulfurization catalyst prepared by thepresently disclosed method using hydrogen, argon, or both as theactivation gas has a BET surface area that is 50-150% greater,preferably 75-120% greater, more preferably 90-100% greater than that ofa CoMoS hydrodesulfurization catalyst prepared using air as theactivation gas.

Preferably, the CoMoS hydrodesulfurization catalyst is mesoporous. In arelated embodiment, the CoMoS hydrodesulfurization catalyst has anaverage pore size of 3-12 nm, 4-9 nm, 5-8 nm, or 6-7 nm. In a preferredembodiment, when hydrogen, argon, or both are used as the activationgas, the CoMoS hydrodesulfurization catalyst has an average pore size of3-8 nm, 4-7.5 nm, or 5-6 nm. In another embodiment, when air is used asthe activation gas, the CoMoS hydrodesulfurization catalyst has anaverage pore size of 8-12 nm, 9-11 nm, or about 9.6 nm. In at least oneembodiment, a CoMoS hydrodesulfurization catalyst prepared by thepresently disclosed method using hydrogen, argon, or both as theactivation gas has an average pore size that is 20-80% greater,preferably 30-60% smaller, more preferably 40-50% smaller than that of aCoMoS hydrodesulfurization catalyst prepared using air as the activationgas.

In one or more embodiments, the CoMoS hydrodesulfurization catalyst hasa total pore volume of 0.05-0.4 cm³/g, 0.08-0.3 cm³/g, 0.1-0.2 cm³/g, or0.15-0.18 cm³/g. In a preferred embodiment, when hydrogen, argon, orboth are used as the activation gas, the CoMoS hydrodesulfurizationcatalyst has a total pore volume of 0.1-0.4 cm³/g, 0.12-0.3 cm³/g,0.15-0.25 cm³/g, or 0.18-0.2 cm³/g. In another embodiment, when air isused as the activation gas, the CoMoS hydrodesulfurization catalyst hasa total pore volume of 0.05-0.095 cm³/g, 0.06-0.09 cm³/g, or 0.07-0.08cm³/g. In at least one embodiment, a CoMoS hydrodesulfurization catalystprepared by the presently disclosed method using hydrogen, argon, orboth as the activation gas has a total pore volume that is 15-80%greater, preferably 25-60% greater, more preferably 40-50% greater thanthat of a CoMoS hydrodesulfurization catalyst prepared using air as theactivation gas.

According to a second aspect, the present disclosure relates to aprocess for desulfurizing a hydrocarbon feedstock comprising asulfur-containing compound. The method involves contacting thehydrocarbon feedstock with a CoMoS hydrodesulfurization catalyst in thepresence of H₂ gas to convert at least a portion of thesulfur-containing compound into a mixture of H₂S and a desulfurizedproduct, and removing H₂S from the mixture, thereby forming adesulfurized hydrocarbon stream. The CoMoS hydrodesulfurization catalystused herein may have similar properties as described for that in thefirst aspect, such as composition, surface area, pore size, pore volume,and/or some other property. The CoMoS hydrodesulfurization catalyst withsimilar properties may be formed via the aforementioned method thatinvolves (i) the one-pot strategy to form the dried mass, and (ii) thesingle-step calcination and sulfidation on the dried mass by followingpreviously specified reaction conditions, such as reagents, solvent,reaction time, hydrothermal treatment temperature, and/or calcinationtemperature. The CoMoS hydrodesulfurization catalyst prepared by themethod of the first aspect may be used directly for the desulfurizingprocess without a separate pre-sulfidation step. Preferably, the CoMoShydrodesulfurization catalyst is not sulfided prior to the contacting.

Preferably, the CoMoS hydrodesulfurization catalyst used herein containscobalt and molybdenum sulfide disposed on a support material comprisingmesoporous silica. Preferably, the CoMoS hydrodesulfurization catalystused herein has a Mo content in a range of 2-10%, preferably 3-9%,preferably 4-8%, preferably 5-7%, or about 6% by weight relative to atotal weight of the CoMoS hydrodesulfurization catalyst. Preferably, theCoMoS hydrodesulfurization catalyst has a Co content in a range of0.02-0.2%, preferably 0.03-0.15%, preferably 0.04-0.1%, preferably0.05-0.08%, preferably 0.06-0.07% by weight relative to a total weightof the CoMoS hydrodesulfurization catalyst. The CoMoShydrodesulfurization catalyst may have a Mo:Co weight ratio of 200:1 to10:1, preferably 150:1 to 25:1, preferably 120:1 to 50:1, preferably110:1 to 70:1, preferably 100:1 to 80:1. Preferably, the CoMoShydrodesulfurization catalyst has a S content in a range of 0.5-5%,preferably 0.9-4%, preferably 1-3%, preferably 1.2-2.5%, preferably1.3-2%, preferably 1.5-1.9%, preferably 1.6-1.8% by weight relative to atotal weight of the CoMoS hydrodesulfurization catalyst. The CoMoShydrodesulfurization catalyst used herein may have a BET surface area of80-400 m²/g, 100-300 m²/g, or 200-250 m²/g. The CoMoShydrodesulfurization catalyst used herein may have an average pore sizeof 3-12 nm, 4-9 nm, 5-8 nm, or 6-7 nm. The CoMoS hydrodesulfurizationcatalyst used herein may have a total pore volume of 0.05-0.4 cm³/g,0.08-0.3 cm³/g, 0.1-0.2 cm³/g, or 0.15-0.18 cm³/g.

The hydrocarbon feedstock may be delivered from a hydrocarbon reservoiror directly from an offshore or an onshore well. For example, thehydrocarbon feedstock may be a crude oil that is produced from an oilwell, particularly from a sour gas oil well. Alternatively, thehydrocarbon feedstock may be a gaseous stream that is supplied directlyfrom an offshore or an onshore well, or a sulfur-containing liquid orgaseous stream, e.g. gaseous ethane, liquid gasoline, liquid naphtha,etc. in a refinery or a petrochemical plant that needs to bedesulfurized.

The hydrocarbon feedstock including a sulfur-containing compound mayalso include various hydrocarbon compounds such as C₁₋₅₀ hydrocarboncompounds, preferably C₂₋₃₀ hydrocarbon compounds, preferably C₃₋₂₀hydrocarbon compounds, depending on the origin of the hydrocarbonfeedstock. In one embodiment, the hydrocarbon feedstock includes C₁₋₂₀normal paraffins, e.g. C₁₋₂₀ alkanes, C₁₋₂₀ isoparaffins, C₁₋₂₀cycloparaffins (i.e. naphthenes) or C₁₋₂₀ cycloparaffins having sidechain alkyl groups. C₁₋₂₀ aromatics or C₁₋₂₀ aromatics with side chainalkyl groups.

Exemplary sulfur-containing compounds include, but are not limited to,H₂S, elemental sulfur, carbon disulfide, dimethyl disulfide, ethyldisulfide, propyl disulfide, isopropyl disulfide, butyl disulfide,tertiary butyl disulfide, thianaphthene, thiophene, secondary dibutyldisulfide, thiols, methyl mercaptan, phenyl mercaptan, cyclohexythiol,methyl sulfide, ethyl sulfide, propyl sulfide, isopropyl sulfide, butylsulfide, secondary dibutyl sulfide, tertiary butyl sulfide,benzothiophene, dibenzothiophene, alkyl benzothiophene, alkyldibenzothiophene, thiocyclohexane, and/or any combination thereof.

In one or more embodiments, the sulfur-containing compound is at leastone selected from the group consisting of a sulfide, a disulfide, athiophene, a benzothiophene, and a dibenzothiophene. In a preferredembodiment, the sulfur-containing compound is a dibenzothiophenecompound. Exemplary dibenzothiophene compounds include, but are notlimited to, dibenzothiophene, 4-methyldibenzothiophene,4,6-dimethyldibenzothiophene, and 4,6-diethyldibenzothiophene. In atleast one embodiment, the sulfur-containing compound isdibenzothiophene, 4,6-dimethyldibenzothiophene, or both.

In one or more embodiments, the sulfur-containing compound may bepresent in the hydrocarbon feedstock at a concentration of 0.01-10%,preferably at least 0.05%, at least 0.1%, at least 1%, at least 3%, atleast 5%, at least 6%, at least 7%, at least 8%, at least 9% by weight,and no more than 10% by weight, relative to a total weight of thehydrocarbon feedstock. In a related embodiment, a concentration of thesulfur-containing compound in the hydrocarbon feedstock is no more than50,000 ppm, preferably no more than 20,000 ppm, preferably no more than10,000 ppm, preferably no more than 5,000 ppm, preferably no more than4,000 ppm, preferably no more than 2,000 ppm. Alternatively, aconcentration of sulfur-containing compound in the hydrocarbon feedstockmay be in a range of 100 to 10,000 ppm, preferably 250 to 7,500 ppm,preferably 500 to 5,000 ppm, preferably 750 to 2,500 ppm, preferably1,000 to 2,000 ppm.

The hydrocarbon feedstock may be in a liquid state or a gaseous state.In view of that, contacting the hydrocarbon feedstock with the CoMoShydrodesulfurization catalyst may be different, depending on the stateof the hydrocarbon feedstock, i.e. the liquid state or the gaseousstate. In one embodiment, the hydrocarbon feedstock is in a liquid stateor in a gaseous state and the hydrocarbon feedstock is passed throughthe CoMoS hydrodesulfurization catalyst via a fixed-bed or afluidized-bed reactor. In another embodiment, the hydrocarbon feedstockis in a gaseous state and the hydrocarbon feedstock is passed over theCoMoS hydrodesulfurization catalyst, or may stay stagnant over the CoMoShydrodesulfurization catalyst, i.e. as an atmosphere to the catalyst.Yet in another embodiment, the hydrocarbon feedstock is in a liquidstate and the hydrocarbon feedstock is mixed with the CoMoShydrodesulfurization catalyst to form a heterogeneous mixture in a batchreactor equipped with a rotary agitator.

The hydrocarbon feedstock may be contacted with the CoMoShydrodesulfurization catalyst in the presence of H₂ gas under favorablereaction conditions to convert at least a portion of thesulfur-containing compound into a mixture of H₂S and a desulfurizedproduct. In one embodiment, the hydrocarbon feedstock is contacted withthe CoMoS hydrodesulfurization catalyst at a temperature in a range of100 to 500° C., 150-450° C., 200-400° C., or 250-300° C. for 0.1-10hours, 0.5-8 hours, 1-6 hours, 2-5 hours, or 3-4 hours. In a preferredembodiment, a pressure of the H₂ gas is in a range of 2 to 10 MPa,preferably 3 to 9 MPa, preferably 3.5-8 MPa, preferably 4-7 MPa,preferably 4.5-6 MPa, or about 5 MPa. A volumetric flow ratio of the H₂gas to the hydrocarbon feedstock may vary depending on the type ofsulfur-containing compound present in the hydrocarbon feedstock. In someembodiments, the volumetric flow ratio of the H₂ gas to the hydrocarbonfeedstock is in a range of 100:1 to 1:100, 80:1 to 1:80, 50:1 to 1:50,40:1 to 1:40, or 30:1 to 1:30.

Under the catalysis of the CoMoS hydrodesulfurization catalyst preparedby the present method, the sulfur-containing compound present in thehydrocarbon feedstock may be hydrodesulfurized via more than onereaction pathways, preferably two reaction pathways including i) adirect desulfurization reaction (DDS) or a hydrogenolysis to formbiphenyl (BP), whereby C—S bonds are cleaved in a single reaction step,and ii) a hydrogenation reaction (HYD), wherein a complex (e.g.cyclohexyl benzothiophene) is formed initially via hydrogenating thesulfur-containing hydrocarbon compound, and C—S bonds of the complex arecleaved subsequently to form desulfurized products (e.g. cyclohexylbenzene (CHB)). The term “k_(DDS)” refers to a rate constant of thedirect desulfurization reaction with a catalyst. In one embodiment, ahydrodesulfurization reaction catalyzed by the CoMoShydrodesulfurization catalyst has a k_(DDS) in a range from 1×10⁻³ to8×3⁻³ min⁻¹, preferably from 2×10⁻³ to 5×10⁻³ min⁻¹, more preferablyfrom 3×10⁻³ to 4×10⁻³ min⁻¹.

The term “k_(HYD)” refers to a rate constant of the hydrogenationreaction with a catalyst. A hydrodesulfurization reaction catalyzed bythe CoMoS hydrodesulfurization catalyst prepared by the present methodusing air as the activating gas does not proceed via hydrogenationpathway (HYD). In one embodiment, a hydrodesulfurization reactioncatalyzed by the CoMoS hydrodesulfurization catalyst prepared by thepresent method using hydrogen, argon, or both as the activating gas hasa k_(HYD) in a range from 0.2×10⁻³ to 2×10⁻³ min⁻¹, preferably from0.4×10⁻³ to 1×10⁻³ min⁻¹, more preferably from 0.5×10⁻³ to 0.7×10⁻³min⁻¹.

In one embodiment, the contacting converts by weight 50-99.8%,preferably at least 55%, preferably at least 60%, preferably at least65%, preferably at least 70%, preferably at least 75%, preferably atleast 80%, preferably at least 85%, preferably at least 90%, preferablyat least 95%, preferably at least 99% of the sulfur-containing compoundpresent in the hydrocarbon feedstock into a mixture of H₂S and adesulfurized product. The method disclosed herein may include removingthe H₂S from the mixture in the presence of an inert gas (e.g. nitrogen)stream to form a desulfurized hydrocarbon stream. “Removing”, as usedherein, may refer to any process of separating, at least one componentfrom a mixture. Exemplary removing processes include, but are notlimited to, distillation, absorption, adsorption, solvent extraction,stripping, and filtration and are well known to those skilled in theart. The removed H₂S may be collected and further supplied to a sulfurmanufacturing plant to produce sulfur-containing products.

In one or more embodiments, the sulfur content of the desulfurizedhydrocarbon stream is by weight 50-99.8%, preferably at least 55%,preferably at least 60%, preferably at least 65%, preferably at least70%, preferably at least 75%, preferably at least 80%, preferably atleast 85%, preferably at least 90%, preferably at least 95%, preferablyat least 99% by weight less than that of the hydrocarbon feedstock priorto the contacting.

It is worth noting that the CoMoS hydrodesulfurization catalyst made viathe presently disclosed method using hydrogen, argon, or both as theactivating gas demonstrates greater catalytic activity than that madeusing air as the activating gas. In one embodiment, the sulfur contentof the desulfurized hydrocarbon stream of a desulfurization processcatalyzed by the CoMoS hydrodesulfurization catalyst prepared usinghydrogen, argon, or both as the activating gas is at least 30% by weightless than that of a desulfurization process catalyzed by the CoMoShydrodesulfurization catalyst prepared using air as the activating gasunder substantially identical conditions (e.g. temperature, pressure,time), preferably at least 35%, preferably at least 40%, preferably atleast 45%, preferably at least 50%, preferably at least 60% by weightless than that of a desulfurization process catalyzed by the CoMoShydrodesulfurization catalyst prepared using air as the activating gasunder substantially identical conditions (see Table 4 of Example 11).

The examples below are intended to further illustrate protocols forpreparing, characterizing the CoMoS hydrodesulfurization catalysts, anduses thereof, and are not intended to limit the scope of the claims.

Example 1

Synthesis of Sulfur-Rich Silica Supported CoMo Nanoparticles

The sulfur-rich silica supported CoMo was prepared by dissolving 1.25 gof pluronic P123 in 30 mL of 2 M HCl solution followed by addition of 10mL deionized water and stirring the mixture for 30 min at 40° C. Then2.45 g of (3-mercaptopropyl)trimethoxysilane (MPMS) was added dropwiseto the continuously stirred mixture. After 1 h of stirring, a solutionof Mo and Co (10 wt. % and 3 wt. %, respectively) was added to themixture and the stirring continued for 20 h before transferring themixture into a Teflon-lined autoclave for hydrothermal synthesis at 90°C. for 24 h. The greenish solid obtained was centrifuged and dried at100° C. overnight before being subjected to calcination treatment. Theelemental composition of the dried greenish sulfur-rich silica supportedCoMo powder (HS_SiO₂_CM) was determined by X-ray fluorescence (XRF)spectrometer as presented in Table 1. The results were obtained byaiming the X-ray source at 5 different points of the sample. Mean value,standard deviation, and relative standard deviation data suggested thatthe mixture was relatively homogeneous.

TABLE 1 Representative elements present in sulfur-rich silica supportedCoMo catalyst before activation Spectrum Si S Co Mo HS_SiO₂_CM 1 35.5756.10 1.25 7.08 HS_SiO₂_CM 2 32.24 57.94 1.09 8.74 HS_SiO₂_CM 3 33.1957.42 0.99 8.40 HS_SiO₂_CM 4 31.79 60.70 1.27 6.24 HS_SiO₂_CM 5 35.4556.07 1.05 7.43 Mean value 33.65 57.65 1.13 7.58 Std. Abw.: 1.59 1.690.11 0.90 Std. Abw. rel. [%]: 4.71 2.94 9.88 11.92

Example 2

Activation of the Sulfur-Rich Silica Supported CoMo

The dried greenish powder was divided into three portions. Each portionwas heated in a tubular furnace at 400° C. for 3 h under the flow ofair, argon, and hydrogen, respectively. Under these conditions, thesulfur was expected to react with the metals to form CoMoS active phaseon the silica support. The formed catalysts are named “Air-treated”,“Ar-treated,” and “H₂-treated,” respectively. A schematic representationof the synthesis procedure is presented in FIG. 1 .

Example 3

Characterization of the Activated CoMoS Catalysts

Textural properties of the catalysts were evaluated via N₂adsorption-desorption isotherm analysis at 77 k using a MicromereticsASAP 2020. The catalysts (approximately 0.1 g each) were initiallydegassed under flowing argon at 523 k for 2.5 h. The BET method was usedto calculate the surface area, whereas absorption branch of BJH methodwas applied to calculate the pore size and pore volume of the catalysts.

FTIR spectra of the catalysts were recorded on a Nicolet 6700 FTIRspectrometer with a wavelength range of 400-4000 cm⁻¹. The FTIR samplepellets were prepared using a mixture of the respective catalyst and KBrat a weight ratio of 1:100.

Catalyst crystallinity and the distribution of CoMo on the silicasupport were determined by scanning the catalysts' X-ray diffractionpattern between 20° to 80° 20 at 40 kV and 40 mA using a Rigaku UltimaIV X-ray diffractometer.

Surface morphology of the catalysts was imaged using a JEOL JSM-6610LVscanning electron microscope. Element mapping with the corresponding EDXspectrum were recorded using an energy dispersive X-ray spectrometer.

The degree of Mo sulfidation of the catalysts due to differentactivation conditions were determined by X-ray photoelectronspectroscopy (XPS) using a PHI 5000 Versa Probe II, ULVAC-PHI Inc.spectroscope.

Example 4

Catalyst Activity Test

All three activated catalysts were pelletized, crushed, and sievedwithin 300-500 microns prior to the catalyst activity test. The activitytest was carried out in a Parr 4590 Micro Bench Top Reactor operated ata pressure of 5 MPa of H₂ and 100 rpm stirring rate. Approximately 15 mgof the activated catalyst was added to 15 mL of model fuel containing1000 ppm DBT in dodecane. The reaction was performed for 4 h after thereaction conditions became stabilized, and the product sampling was doneat one hour interval. A decrease in sample volume due to sampling waswithin 5% range of the total reactant volume. GC-SCD was used to monitorthe decrease in the DBT in model fuel and catalysts activity wascalculated in terms of percent conversion versus reaction time. Theidentity of products and product distribution studies were performedusing GC-MS.

Example 5

Textural Properties

The surface area, pore volume, and pore sizes of the activated catalystsare summarized in Table 2. Typically, large BET surface area and porevolume are indications of better catalysts performance since thereactant molecules are more likely to interact with the active phase ofthe catalysts effectively when the surface area is large. From thetextural property results in Table 2, it was observed that theAir-treated catalyst had the lowest surface area of 30 m²/g, whereas theAr-treated catalyst had the highest surface area of 298 m²/g. TheH₂-treated catalyst had a lower BET surface area than that of Ar-treatedcatalyst, while the former presented a slightly higher microporoussurface area.

TABLE 2 Textural property of the activated catalysts BET MicroporousExternal Microporous pore Total pore Average surface surface areasurface volume volume pore size Catalysts area (m²/g) (m²/g) area (m²/g)(cm³/g) (cm³/g) (nm) Air-treated  30 28 31 0.002 0.083 9.6 Ar-treated298 83 193  0.058 0.187 5.8 H₂-treated 154 92 63 0.054 0.102 7.5

This indicates that the activation condition significantly affects thesurface area of the sulfur-rich silica supported CoMo catalysts. Similarpatterns were observed for both microporous pore volume and total porevolume of all three catalysts. However, it was observed that the averagepore size of the catalysts followed an opposite trend compared with thecatalysts BET surface area. Air-treated and Ar-treated catalystspresented pore size of 9.6 nm and 5.8 nm, respectively. The observedbehavior could be related to possible combustion of the Pluronic P123organic template during the activation process. Generally, theAir-treated catalyst would have the least carbon deposition due to theoxidation of carbon by air, which might open up the mesoporous cavitiesthat were hitherto filled up by surfactant. Therefore the amount ofcarbon deposit on the catalysts may influence their pore volume andsurface area [G. Alonso, M. H. Siadati, G. Berhault, A. Aguilar, S.Fuentes, R. R. Chianelli, Appl. Catal. A Gen. 263 (2004)109-117—incorporated herein by reference]. The N₂ adsorption-desorptionisotherm and pore volume versus pore width plots in FIGS. 2 a-b depictthe level of porosity of the catalysts. The type IV hysteresis loopobserved confirmed the presence of both micropores and mesopores due tothe complexity of the activated catalysts.

Example 6

Fourier Transform Infrared (FTIR) Spectroscopy

FTIR spectra of the catalysts (Air-, Ar-, and H₂-treated) are presentedin FIG. 3A. Peaks characteristics of silica support were observed forall catalysts. The O—H stretching adsorption band (due to silanol orwater adsorption) was observed at 3500 cm⁻¹, while Si—O—Si stretchingvibration and Si—OH were noted at 1050 cm⁻¹ and 750 cm⁻¹, respectively.Interestingly, no peak of thiol group attached to the silica wasobserved in all the activated catalysts. Therefore, it can be inferredthat the thiol has been decomposed due to the activation treatment andwas possibly converted to metal sulfides, hydrogen sulfide, and sulfurdioxide, depending on the activation condition. The Mo—S vibration peakobserved in all catalysts at 490-500 cm⁻¹ [S. Ding, P. He, W. Feng, L.Li, G. Zhang, J. Chen, F. Dong, H. He, J. Phys. Chem. Solids 91 (2016)41-47; and S. Liu, X. Zhang, H. Shao, J. Xu, F. Chen, Y. Feng, Mater.Lett. 73 (2012) 223-225—incorporated herein by reference] confirmed theformation of MoS₂ active phase in all catalysts. Careful observation ofthe peak intensity revealed that the H₂-treated catalyst had arelatively larger amount of MoS₂, and more active phases than those ofthe Ar- and Air-treated catalysts. The peaks observed at 2900 cm⁻¹ and2300 cm⁻¹ were assigned to the —CH₂ and —C≡C— stretching vibrations dueto the decomposition of Pluronic P123 during the catalysts activation.Their peak intensities further supported that the Air-treated catalysthad the least amount of carbon deposit.

Example 7

X-Ray Diffraction (XRD)

The crystallinity and understanding of the CoMo dispersion on silicasupport of the catalysts were elucidated from the X-ray diffractionpatterns shown in FIG. 3B. The observed patterns all showed a broad bandcharacteristic indicating the amorphous nature of silica. This indicatesthat the metals had a relatively good dispersion on the silica support.However, inspection of the spectra also revealed that weak peaks of themetal phases present in the activated catalysts. Firstly, theAir-treated catalyst showed distinctive diffraction peaks at 24 and27.5° 20, which were well resolved peaks of MoO₃ (JC-PDF2-No. 05-0508)[L. O. Aleman-Vazquez, E. Torres-Garcia, J. R. Villagomez-Ibarra, J. L.Cano-Dominguez, Catal. Letters 100 (2005) 219-226]. These diffractionspeaks were not noticed in the Ar- and H₂-treated catalysts, which showedpeaks characteristic of MoS₂ observed at 35 and 60° 20 (QC-PDS No.37-1492) [S. Ding, P. He, W. Feng, L. Li, G. Zhang, J. Chen, F. Dong, H.He, J. Phys. Chem. Solids 91 (2016) 41-47]. Based on the observedresults, it could be concluded that all catalysts had a relatively gooddispersion of the metals due to their poor crystallinity [H. Liu, C.Yin, B. Liu, X. Li, Y. Li, Y. Chai, C. Liu, Energy & Fuels 28 (2014)2429-2436], and the degree of Mo sulfidation was relatively low in theAir-treated catalyst demonstrated by the observed MoO₃ phases.

Example 8

Scanning Electron Microscope (SEM)

SEM images of all activated catalysts are presented in FIGS. 4A-C. Theimages showed that the catalysts composed of particles of irregularsizes and the particle density was larger in Ar- and H₂-treatedcatalysts and lower in Air-treated catalyst. The EDX elemental analysisof the catalysts presented in Table 3 highlighted that carbon depositmight lead to formation of large particle densities of Ar- andH₂-treated catalysts.

TABLE 3 Percent elemental composition of the activated catalystsobtained from EDX and XPS analysis XPS EDX C1S O1S Si2P S2P Mo⁴⁺Mo⁶⁺(3d5/2) Mo⁶⁺(3d3/2) Catalysts C O Si S Co Mo (284 eV) (532 eV) (102eV) (163 eV) (228 eV) (232 eV) (235 eV) Air-treated 41.39 37.94 14.780.90 0.07 4.92 18.78 53.14 26.47 1.12 0.14 0.20 0.14 Ar-treated 55.9025.68 13.53 1.33 0.05 3.51 35.45 37.62 24.93 1.47 0.20 0.20 0.13H₂-treated 57.41 23.20 14.08 1.89 0.03 3.39 44.10 32.00 26.47 2.68 0.390.10 —

Carbon percentages of 41.39, 55.90, and 57.41 were recorded for theAir-, Ar-, and H₂-treated catalysts, respectively. Furthermore, sulfurpercentages of 0.9, 1.33, and 1.89 for Air-, Ar-, and H₂-treatedcatalysts were obtained from the EDX analysis, which meant that MoO₃ wassulfided at a higher degree in H₂-treated catalyst than in Ar-treatedcatalyst, and Air-treated catalyst had the lowest degree of Mosulfidation. This supports the XRD and FTIR results. The mapping ofelements was performed on the catalysts in order to identify thedistribution of all elemental components. FIGS. 5A-F, 6A-F, and 7A-Fshow that every elemental component was evenly distributed in all theactivated catalysts. Therefore, the currently disclosed approach ofsynthesizing supported CoMoS catalysts from sulfur-rich support providesan excellent distribution of the active species on the support.

Example 9

X-Ray Photoelectron Spectroscopy (XPS)

XPS analysis of the activated catalysts was performed to understand theMo phases present in the catalysts and the level of sulfidation achievedthrough different activation approaches. FIGS. 8A-F demonstrated thedeconvoluted XPS spectra of Mo and sulfur, respectively, in theactivated catalysts. The XPS peaks of Mo were identified at 228 eV, 233eV, and 236 eV, which correspond to the Mo⁴⁺(3d_(5/2)), Mo⁶⁺(3d_(5/2)),and Mo⁶⁺(3d_(3/2)) states, respectively. The XPS peak of sulfur wasobserved at 163 eV, which corresponds to the S² (2P_(3/2)) state ofsulfur. The presence of both Mo⁴⁺ and S²⁻ XPS peaks confirmed theformation of the MoS₂ active phase within the catalysts. Furthermore,higher percentages of M⁴⁺ and S²⁻ states in the catalysts imply largeramounts of the active phase. Table 3 summarizes the elementalcomposition of the activated catalysts in their various oxidation statesobtained from the XPS result. Air-treated catalyst had the leastpercentage of Mo⁴⁺(3d_(5/2)) and S²⁻(2P_(3/2)), whereas H₂-treated hadthe largest percentage of Mo⁴⁺(3d_(5/2)) and S²⁻(2P_(3/2)). This furtherconfirms the aforementioned observation from SEM, XRD, and FTIR resultsthat a higher percentage of the active phase was obtained in theH₂-treated catalyst. Based on the characterization results discussedabove, the mechanism of activation is proposed below.

Example 10

Proposed Mechanism of the HS_SiO₂_CM Activation

The HS_SiO₂_CM catalyst was activated at 400° C. for 3 h under the flowof air, Ar, and H₂, respectively. At this activation temperature, thethiol bond in the catalyst is likely to be dissociated and form H₂S. Inthe flow of air, formation of SO₂ is most probable due to oxidation ofthe thiol as shown in equation (1). The formation of SO₂ as well as theoxide nature of the catalyst may hinder the sulfidation process. In theflow of Argon, the decomposition of the thiol yields H₂S and S₂(equation (2)), which are likely to improve the sulfidation of thecatalyst oxide. In the case of H₂, such sulfidation is more efficient asthe metal oxides first get reduced and subsequently sulfided as depictedin equation (3). The decomposition of P123 surfactant during theactivation process may form carbon deposit and oxides of carbon.Typically, Ar- and H₂-treated catalysts are likely to form only thecarbon deposit while the air-treated catalyst forms CO and CO₂ inaddition to the carbon deposit.

$\begin{matrix}{{{HS\_ SiO}_{2}{\_ CM}}\overset{air}{\rightarrow}\left. {{{SiO}_{2}{\_ CoMo}\mspace{11mu}({oxides})} + {H_{2}S} + {SO}_{2}}\rightarrow{{{SiO}_{2}{\_ CoMo}\mspace{11mu}({oxides})} + {{SiO}_{2}{\_ CoMoS}}} \right.} & (1) \\{{{HS\_ SIO}_{2}{\_ CM}}\overset{Ar}{\rightarrow}\left. {{{SIO}_{2}{\_ CoMo}\mspace{11mu}({oxides})} + {H_{2}S} + S_{2}}\rightarrow{{{SIO}_{2}{\_ CoMo}\mspace{11mu}({oxides})} + {{SiO}_{2}{\_ CoMoS}}} \right.} & (2) \\{{{HS\_ SiO}_{2}{\_ CM}}\overset{H_{2}}{\rightarrow}\left. {{{SiO}_{2}{\_ CoMo}\mspace{11mu}({reduced})} + {H_{2}S}}\rightarrow{{SiO}_{2}{\_ CoMoS}} \right.} & (3)\end{matrix}$

Example 11

Catalysts Activity Test

The activity results of the silica supported CoMoS catalysts developedthrough activation of HS_SiO₂_CM via three different treatments arepresented in Table 4. The H₂-treated catalyst with a greater amount ofthe active phases required for the HDS reaction showed the highestpercent conversion of dibenzothiophene (DBT), while air-treated catalystdemonstrated the lowest percent conversion of DBT. The percentconversion of DBT using Ar-treated catalyst was slightly lower than theobserved conversion for H₂-treated catalyst (FIG. 9 ). The disparity inDBT removal capacities of the catalysts is attributed to the activationcondition, where activation under the flow of H₂ has resulted in thelargest amount of Mo sulfidation. Furthermore, BET surface area and porevolume of the catalysts significantly affect the catalysts activity.

TABLE 4 Activity and product distribution in the HDS of DBT for theactivated catalysts after 4 h of reaction Product distribution DBT (%)kHDS × 10³ kDDS × 10³ kHYD × 10³ Catalysts removal (%) CHB BP (min⁻¹)(min⁻¹) (min⁻¹) kDDS/kHYD Air-treated 58.3 — 100 3.65 3.65 0.00 —Ar-treated 72.2 10.2 89.8 5.33 4.79 0.54 8.87 H₂-treated 75.5 10.1 89.95.85 5.26 0.59 8.92

Ar-treated catalyst with the largest surface area showed comparableperformance to the H₂-treated catalyst, even though the former had alower degree of Mo sulfidation. This indicates that large surface areaand total pore volume may also enhance the HDS activity. The carbondeposit formed due to decomposition of organic surfactant may furtherimpact the HDS activity [R. Romero-Rivera, G. Berhault, G. Alonso-Núñez,M. Del Valle, F. Paraguay-Delgado, S. Fuentes, S. Salazar, A. Aguilar,J. Cruz-Reyes, Appl. Catal. A Gen. 433-434 (2012) 115-121—incorporatedherein by reference]. According to previous findings, a large carbondeposit is likely to impact negatively on the HDS activity of catalystsdue to active sites blocking [G. Alonso, M. H. Siadati, G. Berhault, A.Aguilar, S. Fuentes, R. R. Chianelli, Appl. Catal. A Gen. 263 (2004)109-117; and G. Alonso, J. Espino, G. Berhault, L. Alvarez, J. L. Rico,Appl. Catal. A Gen. 266 (2004) 29-40—incorporated herein by reference].Indeed, the air-treated catalyst had lower percent of carbon depositthan that of Ar- and H₂-treated catalysts. However, both microporous andtotal pore volume of the air-treated catalyst were smaller than those ofAr- and H₂-treated catalysts. This indicates that the role of carbondeposit on the catalysts' textural properties and HDS activity is mostlydependent on the synthesis approach through which the carbon isintroduced into the structure of the active metals phases. As reportedby Kelty et al., successful incorporation of carbon at the edges of MoS₂slabs has enhanced its HDS activity [S. P. Kelty, G. Berhault, R. R.Chianelli, Appl. Catal. A Gen. 322 (2007) 9-15—incorporated herein byreference].

Product distribution studies also showed significant variations amongthe catalysts prepared via different activation methods. Previousstudies have shown that the HDS of DBT typically occurs through twomajor pathways: direct desulfurization that forms biphenyl (BP), andhydrogenation that forms cyclohexyl benzothiophene that dissociates fastvia C—S cleavage to form cyclohexyl benzene (CHB). Product distributionresults presented in Table 4 shows that BP was the only product of theHDS reaction using the air-treated catalyst, thus the reaction onlyoccurred via the DDS pathway. However, the HDS reaction using Ar- andH₂-treated catalysts occurred via both DDS and HYD pathways forming BP(approx. 90%) and CHB (approx. 10%). The hydrogenation behavior of Ar-and H₂-treated catalysts suggests their potential HDS applicability onmore refractory sulfur compounds such as dimethyldibenzothiophene, whichare desulfurized effectively through the HYD pathway [P. Michaud, J.Lemberton, G. Pérot, Appl. Catal. A Gen. 169 (1998) 343-353—incorporatedherein by reference]. The disparity in the product selectivity observedamong the catalysts further demonstrates the impact of activationapproach on the HS_SiO₂_CM catalyst.

The kinetic parameters were established assuming the HDS reaction occursvia a parallel pathway. Pseudo-first kinetics was used to calculate therate constants after 4 h reaction time. The rate constants (min⁻¹) ofthe HDS (k_(HDS)), DDS (k_(DDS)), and HYD (k_(HYD)) are presented inTable 5. The k_(HDS) of the activated catalysts was observed to increasein the order of: air-treated <Ar-treated <H_(Z)-treated, however, theratio of the k_(DDS)/k_(HYD) was observed to be nearly the same for Ar-and H₂-treated catalysts. An undefined k_(DDS)/k_(HYD) for air-treatedcatalyst further demonstrated that the reaction occurred only via theDDS pathway. Table 5 presents a fair comparison among reported k_(HDS)of various catalysts and observed k_(HDS) of the currently disclosedH₂-treated catalyst. Interestingly, the observed k_(HDS) is fairlycomparable with reported values, which demonstrates the potential ofthis novel approach. The current approach completely eliminates thesynthesis of metal thiosalts (for unsupported catalysts) and reductionand presulfidation step (for supported catalysts). Therefore, similar orbetter catalytic performance can be achieved without complex synthesissteps by adopting the current approach of catalysts synthesis.

TABLE 5 Comparison of HDS activity of various catalysts based on theirrate constants Catalysts kHDS × 10³ (min⁻¹) Reference TSMN-SP-550 ^(a)6.50 [1] WS-1 ^(b) 0.85 [2] CoMoWS-C14 ^(c) 10.6 [3] H₂-treated 5.85This work ^(a) Single pot synthesis of Ti-SBA-15 NiMo oxides ^(b) WS₂formed from ex situ decomposition of ammonium thiotungstate in N₂ ^(c)CoMoWS obtained by in situ decomposition oftetradecyltrimethylammonium-thiomolybdate-thiotungstate-cobaltate (II)

References: (1) S. A. Ganiyu, K. Alhooshani, S. A. Ali, Appl. Catal. BEnviron. 203 (2017) 428-441; (2) R. Romero-Rivera, G. Berhault, G.Alonso-Núñez, M. Del Valle, F. Paraguay-Delgado, S. Fuentes, S. Salazar,A. Aguilar, J. Cruz-Reyes, Appl. Catal. A Gen. 433-434 (2012) 115-121;and (3) Y. Espinoza-Armenta, J. Cruz-Reyes, F. Paraguay-Delgado, M. DelValle, G. Alonso, S. Fuentes, R. Romero-Rivera, Appl. Catal. A Gen. 486(2014) 62-68, each incorporated herein by reference in their entirety.

Example 12

Series of silica supported CoMoS catalysts were synthesized based on asingle step approach using (3-mercaptopropyl)trimethoxysilane thatdually functions as the silica source and the sulfur precursor in ahydrothermal synthesis approach. The mixture of MPMS, Pluronic P123surfactant, Co and Mo precursors were subjected to hydrothermalsynthesis in an acidic solution for 24 h. This single-step approachaddressed the challenges of synthesizing metal thiosalts precursors andyielded efficient HDS catalysts because of the unique supportpreparation. The synthesized catalysts were exposed to three differentcalcination treatments at 400° C. for 3 h under the flow of air, Ar, andH₂. The HDS performance of the treated catalysts was characterized.

After activation in air, Ar, and H₂, respectively, physico-chemicalproperties of the catalysts were studied. Ar- and H₂-treated catalystswere shown to be supported catalysts with large BET surface area andtotal pore volume, and also demonstrated an effective Mo sulfidation.The H₂-treated catalyst demonstrated the highest HDS activity resultedfrom better active phase properties. Accordingly, the H₂ activation isconsidered the best approach among the three.

The Ar- and H₂-treated catalysts direct the HDS reaction via both DDSand HYD pathways while the air-treated catalyst directs the reaction viathe DDS pathway only. The rate constant of HDS reaction catalyzed byH₂-treated catalyst is comparable with that of recently reportedcatalysts. Other benefits of the current approach include reduction thenumber of synthesis steps, and elimination of the use of toxicsulfidation compounds such as carbon disulfide.

The invention claimed is:
 1. A method of preparing a CoMoShydrodesulfurization catalyst, the method comprising: mixing a nonionictriblock copolymer composed of a central poly(propylene oxide) chainflanked by two poly(ethylene oxide) chains with HCl to form an acidifiedstructural directing surfactant; mixing a molybdenum precursor, a cobaltprecursor, a mercaptoalkyltrialkoxysilane, and the acidified structuraldirecting surfactant, and a solvent to form a reaction mixture;hydrothermally treating the reaction mixture at a temperature of 90 to100° C. then drying to form a dried mass; and calcining the dried massin argon gas thereby forming the CoMoS hydrodesulfurization catalyst,wherein the CoMoS hydrodesulfurization catalyst is disposed on a supportmaterial comprising a mesoporous silica, the CoMoS hydrodesulfurizationcatalyst has a BET surface area of 250-300 m²/g, the CoMoShydrodesulfurization catalyst has a microporous surface area of 83-92m²/g. the CoMoS hydrodesulfurization catalyst has a microporous porevolume of 0.054-0.058 cm³/g, and the CoMoS hydrodesulfurization catalysthas a total pore volume of 0.187-0.102 cm³/g.
 2. The method of claim 1,wherein the CoMoS hydrodesulfurization catalyst is not subjected to asulfidation with a sulfidation reagent.
 3. The method of claim 1,wherein the mercaptoalkyltrialkoxysilane is at least one selected fromthe group consisting of (mercaptomethyl)trimethoxysilane,(mercaptomethyl)triethoxysilane, (mercaptomethyl)tripropoxysilane,(2-mercaptoethyl)trimethoxysilane, (2-mercaptoethyl)triethoxysilane,(2-mercaptoethyl)tripropoxysilane, (3-mercaptopropyl)trimethoxyilane,(3-mercaptopropyl)triethoxysilane, and(3-mercaptopropyl)tripropoxysilane.
 4. The method of claim 3, whereinthe mercaptoalkyltrialkoxysilane is (3-mercaptopropyl)trimethoxysilane.5. The method of claim 1, wherein the solvent is water.
 6. The method ofclaim 1, wherein the dried mass is calcined in the argon gas at atemperature of 250-600° C.
 7. The method of claim 1, wherein the driedmass is calcined in the argon gas for 0.5-8 hours.
 8. The method ofclaim 1, wherein the mercaptoalkyltrialkoxysilane is present in thereaction mixture in an amount of 10-200 g per liter of the reactionmixture.
 9. The method of claim 1, wherein the CoMoShydrodesulfurization catalyst has a Mo content in a range of 2-10% byweight relative to a total weight of the CoMoS hydrodesulfurizationcatalyst.
 10. The method of claim 1, wherein the CoMoShydrodesulfurization catalyst has a Co content in a range of 0.02-0.2%by weight relative to a total weight of the CoMoS hydrodesulfurizationcatalyst.
 11. The method of claim 1, wherein the CoMoShydrodesulfurization catalyst has a S content in a range of 0.5-5% byweight relative to a total weight of the CoMoS hydrodesulfurizationcatalyst.